STDs Flashcards
epidemiology
Single greatest risk factor for contracting an STD – number of sexual partners
Two-thirds of STD cases each year occur in persons in their teens and twenties
Rates for many STDs are higher in African-Americans and Hispanics
Rates are greater in “men who have sex with men” (MSM) than in heterosexuals for all major STDs
Marital status – more common in single, separated, and divorced persons
Higher rates of STDs in users of erectile dysfunction drugs (including HIV)
Congenital or neonatal infections – serious sequelae
-Acquired at birth – C. trachomatis, N. gonorrhoeae, herpes simplex virus
-Syphilis – transmitted transplacentally
-Ophthalmia neonatorum – results from chlamydia or gonorrheal infections
-Neurologic impairment – syphilis, herpes
Pregnancy – all pregnant women should be screened for chlamydia, HIV, syphilis, hepatitis B surface antigen, and hepatitis C antibodies at the first prenatal visit; screen for gonorrhea if women is at high risk (age ≤ 24 years old, previous gonococcal infection, new or multiple sex partners, inconsistent condom use, commercial sex work, drug use).
Gonorrhea etiologic agent
Neisseria gonorrhoeae
Gonorrhea epidemiology
gonorrhea rate in African-Americans was 10.6 times greater than whites in 2014
Highest rates in females 15-24 years old and men 20-29 years old
Risk factors: low socioeconomic status, urban residence, unmarried, previous history of gonorrheal infection
High incidence in prostitutes and IVDA
Associated with increased HIV transmission
Major cause of pelvic inflammatory disease
clinical manifestations of gonorrhea - genital infections in men
Predominant manifestation – acute urethritis
Symptoms – purulent urethral discharge and dysuria
If untreated, spontaneous resolution after several weeks
clinical manifestations of gonorrhea - uncomplicated genital infections in women
Primary site – endocervix
Up to 80% of women are asymptomatic or mildly symptomatic
Symptoms: cervicitis and/or urethritis → increased vaginal discharge, dysuria, urinary frequency, intermenstrual bleeding, menorrhagia
≈ 15% of women with gonorrhea develop PID
Disseminated gonorrhea infection may occur – more common in women
clinical manifestations of gonorrhea - anorectal infection
Most patients are asymptomatic
If symptomatic – acute proctitis → anal pruritis, tenesmus, purulent discharge, rectal bleeding/discharge, rectal pain
clinical manifestations of gonorrhea - pharyngeal infection
Major risk factor – orogenital sexual exposure
Most are asymptomatic; may cause pharyngitis or cervical lymphadenitis
Poor response to some treatments
clinical manifestations of gonorrhea - gonococcal infection in the newborn
Results from passage through the birth canal (may be transmitted in utero)
Most common form – ophthalmia neonatorum
If not treated properly → corneal ulceration and blindness
Gonnorhea diagnosis
Gram stain of a male urethral specimen – gram-negative diplococci within PMNs
Nucleic acid amplification tests (NAAT) – standard of care (urine or endocervical, vaginal, and urethral swabs)
Culture – endocervical or urethral swab
Gonorrhea treatment - potential efficacy of treatment of concurrent infections
Most common coexisting infection – genital chlamydial infection
15-25% of heterosexual men and 35-50% of women are also infected with C. trachomatis → concomitant treatment required***
Incubating syphilis – ceftriaxone is effective in eradicating GC and incubating syphilis
Gonorrhea treatment - concerns for resistant N. gonorrheae
Fluoroquinolones
-In 2015, 22.3% of isolates were resistant to ciprofloxacin
-FQNG more common in MSM (32.1% in 2015 compared to 16.4% in
MSW)
-CDC revised treatment guidelines in April 2007 and no longer recommends fluoroquinolones to treat any gonorrhea case in the United States
Cefixime
-In 2015, 0.5% of isolates had cefixime MICs ≥ 0.25 µg/ml
-CDC revised treatment guidelines in 2010 and no longer recommend cefixime as first-line therapy
Ceftriaxone
-In 2015, 0.3% of isolates had ceftriaxone MIC ≥ 0.125 µg/ml
Azithromycin
-In 2013-15, 2.6% of isolates had azithromycin MIC ≥ 2 µg/ml
treatment of uncomplicated gonococcal infections of the cervix, urethra and rectum***
1) Ceftriaxone 250 mg IM as a single dose PLUS Azithromycin 1 gram PO in a single dose OR doxycycline 100 mg PO BID for 7 days
2) Alternative if ceftriaxone is not available: Cefixime 400 mg PO in a single dose PLUS Azithromycin 1 gram PO in a single dose OR doxycycline 100 mg PO BID for 7 days PLUS Test-of-cure in 1 week
3) If patient has severe cephalosporin allergy: Spectinomycin 2 g IM x 1 PLUS Test-of-cure in 1 week
treatment of uncomplicated gonococcal infection of the pharynx***
Ceftriaxone 250 mg IM in a single dose PLUS Azithromycin 1 gram PO in a single dose OR doxycycline 100 mg PO BID for 7 days
Treatment of disseminated gonococcal infection**
Ceftriaxone 1 gram IM/IV q24h – recommended regimen
Cefotaxime 1 gram IV q8h
Ceftizoxime 1 gram IV q8h
Switch to cefixime 400 mg PO q12h after 24-48 hours of IV therapy to complete 1 week of therapy
treatment of gonorrhea during pregnancy**
Ceftriaxone 250 mg IM x 1 plus azithromycin 1 g PO x 1
Do not treat with tetracycline
Spectinomycin 2 grams IM x 1 if allergic
syphilis etiologic agent
Treponema pallidum (spirochete)
syphilis epidemiology
men 10x more than women
african americans > hispanics and whites
strong association between HIV and syphilis
primary syphilis
After exposure, a painless lesion (chancre) appears at the site of entry (≈ 3 weeks) → highly infectious
Chancre – usually single, dull red macule → papule that erodes and ulcerates; round or oval, indurated and well-marginated
Chancres disappear spontaneously without treatment (3-6 weeks)
secondary syphilis
Develops 2-6 weeks after onset of primary stage
Characterized by a variety of mucocutaneous eruptions → secondary to widespread hematogenous and lymphatic spread
Lesions – anywhere on body including palms of hands and soles of feet
Other symptoms – malaise, fever, pharyngitis, headache, anorexia, arthralgias, generalized lymphadenopathy
Signs disappear in 4-10 weeks
latent syphilis
Patients have positive serologic tests but no other evidence of disease
Divided into early latent and late latent stages
-Early latent – patient is potentially infectious; defined as 1 year from the onset of infections
-Late latent – patient is considered non-infectious (exception – pregnancy)
≈ 25-30% of patients progress to tertiary syphilis
tertiary (late) syphilis
Slowly progressing, inflammatory phase of the disease
Can affect any organ in the body
neurosyphilis
Headache, meningismus, increased CSF leukocyte count and protein
VDRL-CSF – when reactive, diagnostic for neurosyphilis
congenital syphilis
T. pallidum can cross placenta at any time
May result in fetal death, prematurity, or congenital syphilis
Early congenital syphilis – manifestations resemble secondary syphilis
diagnosis of syphilis - microscopic examination of material from lesion
Primary syphilis – presence of T. pallidum on dark-field microscopy
Secondary syphilis – spirochete may be found in cutaneous lesions and lymph nodes
Direct fluorescent antibody test (DFA-TP)
-Greater specificity than dark-field microscopy
-Does require exam of fresh specimen
-More labor intensive and expensive
diagnosis of syphilis - nontreponemal serologic testing
detect reagin (heterogeneous group of antibodies)
Commonly used tests – Venereal Disease Research Laboratory (VDRL); Rapid plasma reagin (RPR), unheated serum reagin test (USR); toluidine red unheated serum test (TRUST)
Positive test indicates presence of any stage of syphilis
Negative in incubating syphilis and early primary syphilis
Used primarily for screening; also useful in following progression of disease and response to therapy (repeat the same test by the same lab)
Seronegativity occurs in patients successfully treated primary and secondary syphilis; early latent – may take up to 4 years; late latent and tertiary syphilis remain seropositive for life
diagnosis of syphilis - treponemal serologic tests
more sensitive than nontreponemal tests; confirmatory
Fluorescent treponemal antibody absorption (FTA-ABS) test
-T. pallidum antigen used to detect antibodies to treponemal organisms
-Becomes positive earlier than nontreponemal tests
-Reactive for life after appropriate treatment of any syphilis stage
T. pallidum hemagglutination assay (TPHA)
T. pallidum passive particle agglutination (TP-PA)
EIAs